Converting Waste Heat to Electricity

With rapid industrialization, the world has seen the development of a number of items or units, which generate heat. Until now this heat has often been treated as a waste, making people wonder if this enormous heat being generated can be transformed into a source of electric power. Now, with the physicists at the University of Arizona finding new ways to harvest energy through heat, this dream is actually going to become a reality.

University of Arizona Research Team:

The research team is headed by Charles Staffor. He is the associate professor of physics, and he along with his team worked on harvesting energy from waste. The team’s findings were published in the September 2010 issue of the scientific journal, ACS Nano.

Justin Bergfield who is an author and a doctoral candidate in the UA College of Optical Sciences shares his opinion, “Thermoelectricity can convert heat directly into electric energy in a device with no moving parts. Our colleagues in the field tell us that they are confident that the device we have designed on the computer can be built with the characteristics that we see in our simulations.”

Advantages:

Elimination of Ozone Depleting materials: Using the waste heat as a form of electric power has multiple advantages. Whereas on one hand, using the theoretical model of molecular thermoelectric helps in increasing the efficiency of cars, power plants factories and solar panels, on the other hand efficient thermoelectric materials make ozone-depleting chlorofluorocarbons, or CFCs, outdated.

More Efficient Design:

The head of the research team Charles Stafford is hopeful about positive results because he expects that the thermoelectric voltage using their design will be 100 times more than what others have achieved. If the design of the team, which they have made on a computer does work, it will be a dream come true for all those engineers, who wanted to catch and make use of energy lost through waste but do not have the required efficient and economical devices to do so.

No need for Mechanics:

The heat-conversion device invented by Bergfield and Stafford do not require any kind of machines or ozone-depleting chemicals, as was the case with refrigerators and steam turbines, which were earlier used to convert waste into electric energy. Now, the same work is done by sandwiching a rubber-like polymer between two metals, which acts like an electrode. The thermoelectric devices are self-contained, need no moving parts and are easy to manufacture and maintain.

Energy is harvested in many ways using the car and factory waste. Car and factory waste can be used for generating electricity by coating exhaust pipes with a thin material, which is a millionth time of an inch. Physicists also take advantage of the law of quantum physics, which though not used often enough, gives great results when it comes to generating power from the waste.

Molecular thermoelectric devices may help in harvesting energy from the sun and reduce the dependence on photovoltic cells, whose efficiency in harvesting solar energy is going down.
How It Works

Though having worked on the molecule and thinking about using them for a thermoelectric device, Bergfield and Stafford had not found anything special till an undergraduate discovered that these molecules had special features. A large number of molecules were then sandwiched between electrodes and exposed to a stimulated heat source. The flow of electrons along the molecule was split in two once it encounters a benzene ring, with one flow of electrons following along each arm of the ring.

The benzene ring circuit was designed in such a way that the electron travels longer distance round the rings in one path, which causes the two electrons to be out of phase when they reach the other side of the benzene ring. The waves cancel out each-other on meeting. The interruption caused in the flow of electric charge due to varied temperature builds up voltage between electrodes.

The effects seen on molecules are not unique because any quantum scale device having cancellation of electric charge will show a similar effect if there is a temperature difference. With the increase in temperature difference, energy generated also increases.

Thermoelectric devices designed by Bergfield and Stafford can generate power that can lit a 100 Watt bulb or increase car’s efficiency by 25%.

hartmano

Ok, but what minimum temperature is required to converting ?

Francisco A Roque

Arizona no longer interest me, or anything from them, I am supporting the boycott

Miguel Dorta

Hey!

Does anybody know about a market place or websites from where you can actually buy alternative energy innovations for just middle class or even poor people so that we can both make a contribution to have a cleaner environment and also save money?

Thank you,

Clint LeRoy

Currently they are experimenting with this type of molecular thermoelectric device but, they call it Thermo-Tunneling. This Thermo-Tunneling Power Generation (TTPG)is currently being investigated by Darpa. Several leading nanotechnology experimenters have mentioned that the efficiency can be as high as 70% efficient. Most are reporting near 30% efficiency and that is much greater then the current 5% efficient thermo-electrics available today.

http://sites.google.com/site/kryorecycling Felix Staratschek

Great idea!
How high should the temperature be?
In summer, houses and halls are often heated by the sun an many processes produces more heat, than the room needs for being warm. To bring this heat back to electricity, when there is no better solution, is a great idea!

bigkahuna

They are developing something very similar at Brealis exploration Limited… called power chips/ heat chips. They have been for about 10 years. They just seem to be stuck on fine tuning the technology and so on to get it moving. They get cooling basically using the same concept in reverse… put in electric and pull the heat out instead of the reverse. Cool Chips.

Awesome concept that seems to be a year or two away from reality. I thought they would be in the market a year or two ago but thats how difficult and expensive it is to get it all working.

Clint LeRoy

The temperature at which this material is the most effective is around >1000°F. Carbon Nano Particles are the key to the release of the electrons. www dot powerchips dot gi = ‘Powerchips plc’ a British company finalizing bring this technology to reality. Peswiki also has a write up worth reading.

Asaf Shalgi

Great concept. Converting waste and heat to energy is a definite plus. Yet I’m still kind of fuzzy about the details. How high and how much?

http://www.hotspotenergy.com/ Dan Diver

waste heat recovery is affordable and available in residential and small business settings. it’s not just for the wealthy and industrial businesses.

María González

Hi all,
does anyone know about a device or system already available in the market to convert waste heat to electricity? Or is it everything still in the Lab?

ARL1

Seem you’ve all forgotten about the Organic Rankine Cycle- designed by William Rankine of Edinburgh Scotland- were you use a liquid with a low boiling point.in a sealed unit to expand through a turbine and then cool – with no waste . http://en.wikipedia.org/wiki/Organic_Rankine_cycle